/*
 * contrib/hstore/crc32.c
 *
 * Both POSIX and CRC32 checksums */

#include <sys/types.h>
#include <stdio.h>
#include <sys/types.h>

#include "crc32.h"

/*
 * This code implements the AUTODIN II polynomial
 * The variable corresponding to the macro argument "crc" should
 * be an unsigned long.
 * Oroginal code  by Spencer Garrett <srg@quick.com>
 */

#define _CRC32_(crc, ch) (crc = (crc >> 8) ^ crc32tab[(crc ^ (ch)) & 0xff])

/* generated using the AUTODIN II polynomial
 *	x^32 + x^26 + x^23 + x^22 + x^16 +
 *	x^12 + x^11 + x^10 + x^8 + x^7 + x^5 + x^4 + x^2 + x^1 + 1
 */

static const unsigned int crc32tab[256] = {
    0x00000000,
    0x77073096,
    0xee0e612c,
    0x990951ba,
    0x076dc419,
    0x706af48f,
    0xe963a535,
    0x9e6495a3,
    0x0edb8832,
    0x79dcb8a4,
    0xe0d5e91e,
    0x97d2d988,
    0x09b64c2b,
    0x7eb17cbd,
    0xe7b82d07,
    0x90bf1d91,
    0x1db71064,
    0x6ab020f2,
    0xf3b97148,
    0x84be41de,
    0x1adad47d,
    0x6ddde4eb,
    0xf4d4b551,
    0x83d385c7,
    0x136c9856,
    0x646ba8c0,
    0xfd62f97a,
    0x8a65c9ec,
    0x14015c4f,
    0x63066cd9,
    0xfa0f3d63,
    0x8d080df5,
    0x3b6e20c8,
    0x4c69105e,
    0xd56041e4,
    0xa2677172,
    0x3c03e4d1,
    0x4b04d447,
    0xd20d85fd,
    0xa50ab56b,
    0x35b5a8fa,
    0x42b2986c,
    0xdbbbc9d6,
    0xacbcf940,
    0x32d86ce3,
    0x45df5c75,
    0xdcd60dcf,
    0xabd13d59,
    0x26d930ac,
    0x51de003a,
    0xc8d75180,
    0xbfd06116,
    0x21b4f4b5,
    0x56b3c423,
    0xcfba9599,
    0xb8bda50f,
    0x2802b89e,
    0x5f058808,
    0xc60cd9b2,
    0xb10be924,
    0x2f6f7c87,
    0x58684c11,
    0xc1611dab,
    0xb6662d3d,
    0x76dc4190,
    0x01db7106,
    0x98d220bc,
    0xefd5102a,
    0x71b18589,
    0x06b6b51f,
    0x9fbfe4a5,
    0xe8b8d433,
    0x7807c9a2,
    0x0f00f934,
    0x9609a88e,
    0xe10e9818,
    0x7f6a0dbb,
    0x086d3d2d,
    0x91646c97,
    0xe6635c01,
    0x6b6b51f4,
    0x1c6c6162,
    0x856530d8,
    0xf262004e,
    0x6c0695ed,
    0x1b01a57b,
    0x8208f4c1,
    0xf50fc457,
    0x65b0d9c6,
    0x12b7e950,
    0x8bbeb8ea,
    0xfcb9887c,
    0x62dd1ddf,
    0x15da2d49,
    0x8cd37cf3,
    0xfbd44c65,
    0x4db26158,
    0x3ab551ce,
    0xa3bc0074,
    0xd4bb30e2,
    0x4adfa541,
    0x3dd895d7,
    0xa4d1c46d,
    0xd3d6f4fb,
    0x4369e96a,
    0x346ed9fc,
    0xad678846,
    0xda60b8d0,
    0x44042d73,
    0x33031de5,
    0xaa0a4c5f,
    0xdd0d7cc9,
    0x5005713c,
    0x270241aa,
    0xbe0b1010,
    0xc90c2086,
    0x5768b525,
    0x206f85b3,
    0xb966d409,
    0xce61e49f,
    0x5edef90e,
    0x29d9c998,
    0xb0d09822,
    0xc7d7a8b4,
    0x59b33d17,
    0x2eb40d81,
    0xb7bd5c3b,
    0xc0ba6cad,
    0xedb88320,
    0x9abfb3b6,
    0x03b6e20c,
    0x74b1d29a,
    0xead54739,
    0x9dd277af,
    0x04db2615,
    0x73dc1683,
    0xe3630b12,
    0x94643b84,
    0x0d6d6a3e,
    0x7a6a5aa8,
    0xe40ecf0b,
    0x9309ff9d,
    0x0a00ae27,
    0x7d079eb1,
    0xf00f9344,
    0x8708a3d2,
    0x1e01f268,
    0x6906c2fe,
    0xf762575d,
    0x806567cb,
    0x196c3671,
    0x6e6b06e7,
    0xfed41b76,
    0x89d32be0,
    0x10da7a5a,
    0x67dd4acc,
    0xf9b9df6f,
    0x8ebeeff9,
    0x17b7be43,
    0x60b08ed5,
    0xd6d6a3e8,
    0xa1d1937e,
    0x38d8c2c4,
    0x4fdff252,
    0xd1bb67f1,
    0xa6bc5767,
    0x3fb506dd,
    0x48b2364b,
    0xd80d2bda,
    0xaf0a1b4c,
    0x36034af6,
    0x41047a60,
    0xdf60efc3,
    0xa867df55,
    0x316e8eef,
    0x4669be79,
    0xcb61b38c,
    0xbc66831a,
    0x256fd2a0,
    0x5268e236,
    0xcc0c7795,
    0xbb0b4703,
    0x220216b9,
    0x5505262f,
    0xc5ba3bbe,
    0xb2bd0b28,
    0x2bb45a92,
    0x5cb36a04,
    0xc2d7ffa7,
    0xb5d0cf31,
    0x2cd99e8b,
    0x5bdeae1d,
    0x9b64c2b0,
    0xec63f226,
    0x756aa39c,
    0x026d930a,
    0x9c0906a9,
    0xeb0e363f,
    0x72076785,
    0x05005713,
    0x95bf4a82,
    0xe2b87a14,
    0x7bb12bae,
    0x0cb61b38,
    0x92d28e9b,
    0xe5d5be0d,
    0x7cdcefb7,
    0x0bdbdf21,
    0x86d3d2d4,
    0xf1d4e242,
    0x68ddb3f8,
    0x1fda836e,
    0x81be16cd,
    0xf6b9265b,
    0x6fb077e1,
    0x18b74777,
    0x88085ae6,
    0xff0f6a70,
    0x66063bca,
    0x11010b5c,
    0x8f659eff,
    0xf862ae69,
    0x616bffd3,
    0x166ccf45,
    0xa00ae278,
    0xd70dd2ee,
    0x4e048354,
    0x3903b3c2,
    0xa7672661,
    0xd06016f7,
    0x4969474d,
    0x3e6e77db,
    0xaed16a4a,
    0xd9d65adc,
    0x40df0b66,
    0x37d83bf0,
    0xa9bcae53,
    0xdebb9ec5,
    0x47b2cf7f,
    0x30b5ffe9,
    0xbdbdf21c,
    0xcabac28a,
    0x53b39330,
    0x24b4a3a6,
    0xbad03605,
    0xcdd70693,
    0x54de5729,
    0x23d967bf,
    0xb3667a2e,
    0xc4614ab8,
    0x5d681b02,
    0x2a6f2b94,
    0xb40bbe37,
    0xc30c8ea1,
    0x5a05df1b,
    0x2d02ef8d,
};

unsigned int crc32_sz(char* buf, int size)
{
    unsigned int crc = ~((unsigned int)0);
    unsigned char* p = NULL;
    int len, nr;

    len = 0;
    nr = size;
    for (len += nr, p = (unsigned char*)buf; nr--; ++p)
        _CRC32_(crc, *p);
    return ~crc;
}
